The basic material handling scraper includes a tractor pivotally connected to a scraper bowl with both being supported by wheels. The bowl is equipped with a scraper blade which separates earth from the terrain over which the scraper is moving. This blade is normally situated in the forward portion of the bowl with the support wheels being located on the rear portion of the bowl. There is normally a hydraulic connection by rams between the tractor and the bowl which is controlled by the operator to lower the bowl into engaging position with the material beneath the bowl. As the vehicle moves over the material, the cutting action of the blade and the forward motion of the vehicle force the separated material into the bowl. Upon loading the bowl to its full capacity the operator raises the bowl to permit transport of the carried material to its unloading location.
The performance of the basic material handling scraper has been adversely affected in the past by the soil conditions in which it must operate. One major limitation to the efficient removal of material has been the constant adjustment which must be made by the operator to allow for uneven surface characteristics of the soil which is being removed. The operator must continually raise and lower the scraper blade to avoid slippage of the drive wheel, stalling of the engine or scalloping of the finished surface which can result from the depth variation of the soil surface and the density of the material being removed. A second limitation to the effectiveness of the basic scraper also results from these variations in soil conditions which adversely affect the flow of separated material from the front of the bowl to the rear of the bowl thereby decreasing the effective moving capacity of the scraper.
A considerable burden is therefore placed on the operator as any such adjustments of the scraper bowl position have necessarily been controlled manually while simultaneously attending to the steering of the scraper vehicle and to various other adjustments. To make efficient use of the scraper, the operator must continually estimate the optimum scraper bowl position for successive stages of material removal. Since the operator is not generally situated at a position where it is convenient to observe the scraper action, and since he cannot directly sense the forces reacting against the scraper, there is a great potential for inconsistent performance. This continued concentrated attention on the part of the operator results in fatigue and thus shorter shifts to achieve reasonably satisfactory operation. Additionally, inefficient manual adjustment typically requires additional movement of the scraper and therefore increased stress to the mechanical and hydraulic components.